The afterimage (in a complementary color) that is retained briefly by the eye after the stimulus is removed.Examples: Stare at the + in the middle of the blue figure for 15-30 seconds. Then move your gaze to the + in the center of the white square on the right.demonstration of afterimage The reversal of colors you saw was this phenomenon called an afterimage. Note how briefly (or how long) the afterimage endured before it was gone.Here are links to three interactive demonstration of afterimages. You must use a JAVA-capable browser to see them properly: the first one, second: "put the fish in the fishbowl," and third: "change the colors of this flag."Also see colorblind, optical illusion, persistence of vision, sight, and subliminal message or subliminal advertising.